1. Identify the proper distance between the right eye and rear sight when aiming the AT-4.
2. Given an illustration of moving targets, identify the correct placement of the front sight lead posts.
3. Recognize the "steady hold" technique for firing the AT-4. 4. Identify the four types of firing positions for the AT-4.
5. Identify the danger zones of the backblast in an infantry fighting position. 6. Identify the conditions a building must meet to fire an AT-4 from inside it. To be proficient with the AT-4, you must be able to detect targets, determine ranges to targets, and hit the targets. There are many variables affecting your ability to detect and determine the ranges to targets. However, the factors affecting your ability to fire and hit the target are relatively constant. Essentially, you must be able to assume a firing position which enables you to hold the AT-4 so you can fire it without disturbing the alignment. The skills required are known as AT-4 marksmanship fundamentals. You will cover these skills in the following paragraphs.
The integrated act of shooting applies the skill necessary to fire an AT-4 accurately. The components of the integrated act of shooting are aiming, steady hold, trigger manipulation, and firing position(s).
2401. Aiming
a. Eye relief. To sight the AT-4, first determine the range to the target. Once you determine the range, place the AT-4 in position on the right shoulder so the right eye is 60-80 millimeters (2.5 to 3 inches) from the rear sight.
b. Sight picture. In aiming, you are concerned with correctly pointing the AT-4 so the cartridge hits the target. To do this, you must have the rear sight, the front sight posts, and the target (or aiming point) in proper relationship which is known as sight picture. A correct sight picture is obtained when the sights are properly aligned and the aiming point (target) is in correct relationship to the front sight posts (figure 2-18). The sight picture includes two basic elements: sight alignment and placement of the front sight lead posts.
Fig 2-18. Correct sight picture.
Warning: Do not place your eye against the rear sight when firing. Keep it 2 1/2 to 3 inches away. Recoil may cause injury.
(1) Sight Alignment. To obtain correct sight alignment, the sights must be aligned (figure 2-19). Notice that the top center of the front sight posts are exactly in the center of the rear sight peephole. Ensure proper sight alignment by looking through the rear sight peephole and focus your eye on the front sight post. The white line fits inside the bottom half of the 2mm peephole (figure 2-19). By doing this, you can detect and correct any errors in sight alignment.
Note: The shooter can adjust his alignment by moving his head forward or backward. The front sight has three sight posts and a semicircular white line under the sight posts (figure 2-19).
Fig 2-19. Correct sight alignment.
(2) Correct Placement of Front Sight Lead Posts. (See figure 2-20.)
(a) For stationary targets or vehicles moving directly toward or away from you, place the center post at the center of the visible mass of the targets.
(b) For slow moving targets, place the center post at the front in which direction the vehicle is moving.
(c) For fast moving targets (more than 10 miles per hour).
1. If the target is moving to the right, place the left lead post at the center of mass.
2. If the target is moving to the left, place the right lead post at the center of mass.
3. Oblique moving targets, see (b) above.
c. Importance of Sight Alignment
(1) At some point in marksmanship training, you may experience difficulty in hitting the target because of errors in aiming. The trouble may be either incorrect sight
alignment or improper placement of the aiming point.
(a) If you understand the principles of aiming, you will rarely make both errors simultaneously. The reason for this lies in your inability to focus on two objects at different distances at the same time. If you focus on the aiming point, the AT-4 sights will appear hazy and indistinct; therefore, the problem is whether sight alignment or placement of the aiming point is of greater importance to the shooter. An error in either can cause the round to miss the aiming point.
(b) Sight alignment is the relationship between the front and rear sights with respect to the shooter's eye. On the battlefield, a slight error in sight alignment results in an error that increases proportionately as the range to the target increases. (c) On the battlefield, a slight error in placing the aiming point can still result in a
point-of-aim hit. For example, you could be several inches off your desired aiming point, center of visible mass, and still hit an enemy target. However, if the error was caused by sight alignment, the round would miss by as much as several feet, depending on the range. The correct relationship between the front sight post and the rear sight peephole, sight alignment, is more important than the placement of the aiming point.
(2) Once the range and lead have been determined, you and your fellow Marine, on command, engage the target until it is destroyed. Under ideal conditions, pair-firing is preferred over sequence firing. It permits you to obtain target hits faster because the succeeding shot can be ready to fire as soon as the previous round impacts.
(a) Since it is important to obtain and hold correct sight alignment when firing, you must concentrate on alignment as the first and last steps in aiming. That is, you must first concentrate on getting proper sight alignment, then establish the proper aiming point to complete the sight picture. Then, as you start to depress the trigger, you can again concentrate on maintaining correct sight alignment. At no time, while depressing the trigger, should you divert your concentration from the front sight post and from maintaining correct sight alignment. These steps should become an automatic process.
(b) No matter how quickly you obtain sight alignment and sight picture, you can still only do one at a time. Therefore, focus first on the front sight post to obtain correct sight alignment and then focus on placing the aiming post to complete the sight picture. By shifting or adjusting the position of the AT-4 as necessary (and finally as you start to depress the trigger), devote total
concentration back to the front sight post and maintain proper sight alignment on the target (figure 2-19).
2402. Firing
a. Steady Hold. When firing the AT-4, you should apply "steady hold." As the term implies, steady hold is the technique of holding the AT-4 as steady as possible while aligning the sight and firing. To ensure the proper sight picture and sight alignment are maintained until the AT-4 is fired, hold the AT-4 in a tight, comfortable position so the AT-4 becomes a natural extension of the body (figure 2-21). With the left hand, grasp the carrying sling where it is attached to the AT-4 near the muzzle. Hold down the red safety catch with the index and middle fingers of the right hand. The index finger and knuckle will lie naturally alongside the forward edge of the firing mechanism. Pull on the carrying sling with the left hand and at the same time, pull back to the rear with the right hand. This helps to get the shoulder stop fully seated into the pocket of the shoulder. Hold the elbows close to the body to aid in balance and control and to counter jerking and flinching.
b. Trigger Manipulation. The trigger for the AT-4 is a red button on the right side of the weapon. To fire the AT-4, apply pressure straight forward with the thumb of the right hand in a steady, smooth movement (figure 2-22). Proper trigger manipulation can be developed by dry-fire practice with an expended AT-4 or AT-4 training devices.
Fig 2-22. Trigger manipulation. 2403. Firing Positions
The AT-4 is fired from the right shoulder only. You may fire it in the standing, kneeling, sitting, or prone positions. The exact position may vary slightly to allow for the shape of the shooter's body. Any of these positions can be used for engaging moving targets, but the standing and kneeling positions are recommended. These two positions allow the shooter to track a moving target easily. Situation, terrain, and individual preference should govern the selection of the best position. Whenever possible, use a supported position. A supported position is more stable and helps you to fire accurately.
a. Standing Position
(1) The standing position is similar to the off-hand position for firing a rifle (figure 2-23). To assume the proper standing position, raise the AT-4 about shoulder level, keeping the AT-4 pointed towards the target while rotating your body under the AT-4 by doing a half-left face. Spread your feet a comfortable distance apart and place the AT-4 on your right shoulder. Your body should be balanced with the hips level. Your left (non-firing) hand should be directly under the front of the AT-4 grasping the carrying sling. Place your left elbow against the body for stability. Grasp the firing mechanism with your right (firing) hand and keep your right elbow placed tightly against your body.
Fig 2-23. Standing position.
(2) To track in the standing position, turn your body from the waist up; do not move your feet. The standing position will expose you more than any other position; therefore, use it when firing from behind a protective barrier, such as a wall or a fighting position. Since the standing position is the least stable position, use support whenever possible.
b. Kneeling Position. There are two satisfactory kneeling positions.
(1) The first kneeling position is similar to the kneeling supported position for firing a rifle (figure 2-24). To assume this kneeling position, first assume the standing position. Kneel on your right knee and point the left leg towards the target. Keep your left foot at a right angle and opposite your right knee, forming a right angle to the ground with the left leg. Sit back on your right heel while shifting your weight forward. Rest your left elbow just forward of your left knee. Avoid bone-to-bone contact. Hold your right elbow firmly against the body.
(2) The second kneeling position is a modification of the first kneeling position (figure 2-25). This kneeling position is the best position for tracking moving targets. To get into this kneeling position for engaging moving targets, first assume the standing position. Kneel on your right knee, keeping your thigh of the right leg vertical. Keep your buttock and back straight. Point your left leg towards the target, keeping your left foot at a right angle and opposite your right knee. Keep your left thigh parallel to the ground. Keep your elbows tucked against your sides.
Fig 2-24. First kneeling position.
(3) Either position may be used when firing at stationary or moving targets; however, the modified version allows tracking similar to the standing position. Maximum use of protective barriers and supported positions are essential with the kneeling positions to increase stability and reduce vulnerability.
c. Sitting Position. There are two satisfactory sitting positions. The sitting positions are suitable for firing at stationary targets and are more stable than the kneeling positions.
(1) For the first position, keep the AT-4 pointed towards the target and execute a half-left face. Sit with your legs crossed and place the AT-4 on your right shoulder. Lean slightly forward from the hips and rest your elbows forward of the knees to avoid bone-to-bone contact (figure 2-26).
(2) To assume the second sitting position, keep the AT-4 pointed towards the target and execute a half-left face. Sit with your legs partially extended and well apart and place the AT-4 on your right shoulder. This position is primarily used on a downward slope, so dig your heels in the ground to keep from sliding down. Rest your elbows forward of the knees to avoid bone-to-bone contact (figure 2-27).
Fig 2-26. First sitting position.
d. Prone Position
(1) To get into the prone position (figure 2-28), first lay the launcher on the ground, pointed toward the target. Then lie on your stomach at an angle of not less than 90 degrees to the line of fire to keep your body clear of the backblast. Your body should be straight and your right leg should be directly on a line running through your right hip and right shoulder. Move your left leg to the left as far as possible without discomfort. Keep both heels as close to the ground as possible, with your right eye lined up with the sights. Tracking a moving target from the prone position is not recommended because your movement is limited and your legs and feet may be injured by the backblast due to changing the position of the launcher.
Warning: Failure to maintain a 90-degree angle in the prone position may cause injury from the backblast.
Fig 2-28. Prone position.
(2) Although the prone position is the least stable position, you can increase stability if you use support. The prone position also affords protection.
2404. Infantry Fighting Position
a. You can fire the AT-4 from the standard infantry fighting position (figure 2-29), but you must consider several points to increase accuracy and to minimize the danger to friendly troops from the backblast. When firing from the infantry fighting position, you lean against the rear wall to ensure that the venturi protrudes past the rear of the position. Your elbows are not supported. When an AT-4 is fired from the two-man infantry fighting position, the Marine who's not firing must be clear of the backblast. Fighting positions should be constructed so one position is not located in the backblast danger zone of another.
Fig 2-29. Infantry fighting position (top view).
b. The area immediately to the rear of an AT-4 must not have walls, large trees, or any other obstructions within 5 meters (Zone A) that will deflect the backblast onto you. The backblast danger area (Zone B) is 60 meters deep with a 90-degree fan from the rear of the weapon (figure 2-30).
2405. Firing From Enclosures (Combat Only)
a. When employed in multistoried buildings, the AT-4 should be positioned on upper levels for maximum coverage.
b. Fire from a building only when the following conditions are met: (1) The building must be of sturdy construction.
(2) The ceiling must be at least 7 feet high.
(3) The room floor size must be at least 15 by 12 feet.
(4) There must be an opening of at least 20 square feet to the rear of the AT-4 for the backblast pressure to escape. An open door (7 feet high by 3 feet wide) would provide adequate ventilation.
(5) All glass must be removed from the windows, and all loose objects removed from the room.
(6) All Marines within the room must be forward of the backblast area of the AT-4. (7) All Marines in the room must protect their hearing with ear plugs when the AT-4 is
fired.
(8) The muzzle of the AT-4 must protrude 6 inches beyond the opening from which the AT-4 will be fired.
Lesson Summary: In this lesson, you covered the proper sight alignment, sight picture, and the different firing positions. You also covered how to fire and what safety precautions to take when firing from the different positions. In the next lesson, you will cover the techniques of firing and how to determine range when engaging the enemy with the AT-4.
Lesson 5. TECHNIQUES OF FIRE AND RANGE DETERMINATION